Pump assembly

ABSTRACT

A pump assembly having a drive module with a stator, a rotor held on a shaft so as to be rotatable relative to the stator, and a housing that circumferentially encloses a portion of the stator. An impeller is held on the shaft, and a hydraulic unit has an intake port through which liquid can be delivered to the impeller. An adapter is connected to the drive module on one side and to the hydraulic unit on the other side. A can body extends between the rotor and the stator of the drive module and encloses the rotor on an end face facing away from the impeller. A can flange adjoins the can body on a side facing the impeller and projects radially outward from the can body. A tubular section circumferentially encloses the impeller at least in part and delimits a pump chamber containing the impeller.

This nonprovisional application claims priority under 35 U.S.C. §119(a)to German Patent Application No. 10 2014 109 625.8, which was filed inGermany on Jul. 9, 2014, and which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pump assembly, particularly forwater-carrying cleaning appliances, comprising a drive module with astator, with a rotor held on a shaft of the drive module so as to berotatable relative to the stator, and with a housing thatcircumferentially encloses at least sections of the stator, comprisingan impeller for pumping liquid that is held on the shaft and comprisinga hydraulic unit with an intake port through which the liquid can bedelivered to the impeller.

2. Description of the Background Art

In water-carrying cleaning appliances such as dishwashers and washingmachines, pump assemblies are provided in order to circulate water towhich detergent has been added. The cleaning effect is based on thecircumstance that the material to be cleaned, such as laundry or dishes,is wetted with the water and the detergent therein, and is cleansed bythe action of the detergent. In addition, dirt and impurities can bemechanically removed by the pressurized liquid formed of water anddetergent. Furthermore, the liquid is heated to improve the cleaningeffect. Heaters, which usually are electrically operated, are providedin the cleaning appliances for this purpose.

It is known in this context to implement the circulation pumpindependently of the heater and to provide it separately in the cleaningappliance. It is likewise known to integrate the heater and the pumpassembly. The heater in this case is provided in a pump housing andaccordingly is a component of a flow-forming, hydraulic part of thepump. An impeller driven by an electric motor establishes the hydraulicpressure necessary for pumping the liquid. The liquid flows past asurface that works together with the heater, and is heated.Comparatively good heat transfer is achieved in this design,particularly by reason of relatively high turbulence in the liquid. Inview of this, when the heater is integrated into the pump assembly, theheater can be small in size and the heat-transmitting surface can becompact. In addition, good energy values are achieved for the heaterintegrated into the pump assembly.

At the same time, due to increasing demands for energy efficiency ofcleaning appliances, modern pump assemblies are driven by synchronousmotors. The asynchronous motors that previously were employed onlyinadequately fulfill the energy requirements due to their sometimeslimited efficiency. An additional advantage of synchronous motors isthat a magnetic air gap between a stator of the synchronous motor and arotor that is mounted on a shaft so as to be rotatable with respectthereto can be made comparatively large. Consequently, it is possible toprovide a can between the stator and the rotor. The rotor is located ina can body, and is surrounded by the liquid. It is advantageous herethat there is no longer any need for a dynamic seal between the drivemodule on the one side and the hydraulic unit on the other side. Thehydraulic unit can be prefabricated as a subassembly and installed as awhole or connected to the drive module.

Known from DE 10 2004 011 365 A1, which corresponds to U.S. Pat. No.7,293,958, is a hydraulic unit for a pump assembly in which the heateris provided at one end of an essentially cylindrical pump chamberadjacent to an intake port through which the liquid enters the pumpchamber and is delivered to the impeller. The walls of the pump chamberare made of a thermoplastic material as part of the hydraulic unit. Theheater has a stainless steel sheet formed into a saucer shape in whichis embedded an electrically operated heating element. The walls of thehydraulic unit additionally include a spiral baffle for the liquid. Thespiral baffle is shaped such that a flow cross-section increases towarda discharge port of the hydraulic unit provided for discharging theliquid. In this regard, the pump housing and the heater constitute afluidic unit that is functionally and spatially integrated to a greatdegree.

Known from EP 2 384 685 A1, which corresponds to U.S. Pat. No.8,245,718, is a pump assembly with an integrated heater, in which theheater is essentially cylindrical or tubular in design andcircumferentially surrounds the impeller provided in the pump chamber. Asynchronous motor is provided to operate the impeller. A can is providedbetween the stator and the rotor of the synchronous motor for hermeticseparation. The heater that circumferentially surrounds the impeller isconnected to a can flange in a sealed manner. The pump chamber is closedat the end face by a pump cover made of a thermoplastic material. Theintake port and the discharge port of the hydraulic unit are integralcomponents of the cover in this design. As a result of the orientationof the ports, however, a redirection of the liquid by 180° is required,with the consequence that the hydraulic efficiency of the pump assemblyis relatively low.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a pumpassembly such that a heater can be integrated into the pump assembly ina simple, flexible, and needs-based manner, and at the same time suchthat high fluidic quality and good efficiency are achieved for the pumpassembly.

In an embodiment, between a drive module and a hydraulic unit, anadapter, which is connected to the drive module on one side and to thehydraulic unit on the other side, which has a can body that can extendbetween the rotor and the stator of the drive module and encloses therotor on an end face facing away from the impeller, which has a canflange adjoining the can body on a side facing the impeller, wherein thecan flange projects radially outward from the can body at least insections, which has a tubular section that circumferentially enclosesthe impeller at least in part and that delimits a pump chambercontaining the impeller, and which has a discharge port formed on thetubular section for discharging the liquid from the pump chamber.

An advantage of the invention is that the provision of the adapterbetween the hydraulic unit and the drive module separates the fluidicunit previously implemented in accordance with the prior art. Inparticular, the intake port can be implemented as part of the hydraulicunit, while the discharge port can be formed on the adapter. At the sametime, the division results in a spatial separation that benefits theflexible integration of the heater in the pump assembly. In particular,a variety of options for integrating the heater are created, so that asuitable heating concept can be chosen in accordance with needs, and theheater can be designed with the appropriate output and can be placed inan application-specific position.

According to an embodiment of the invention, the pump assembly ismodular in design. In this regard, provision is made that a choice of afirst hydraulic unit or at least one additional hydraulic unit of thepump assembly can be attached to the adapter. At least the firsthydraulic unit or the at least one additional hydraulic unit has aheater for heating the liquid. The modular design of the pump assemblyresults in additional options for geometric and functional variationsthat benefit the integration of the same pump assembly in differentwater-carrying cleaning appliances. In this regard, providing a modularsystem for the pump assembly can foster the use of common parts, and theproduction rate can be increased with the manufacture of the commonparts. As a result of the increase in the production rate, thecost-effectiveness of the pump assembly according to the invention isimproved significantly as compared to current-day concepts. At the sametime, the opportunity is afforded of responding flexibly toapplication-specific features or customer-specific desires andspecifications simply by exchanging the hydraulic unit.

At least one, or two or more hydraulic units, have the heater forheating the liquid. The heater can be associated circumferentially withthe intake port, for example, and heat the liquid as it flows into thepump chamber holding the impeller. For example, the heater can beprovided between a housing component of the hydraulic unit facing theimpeller at the end face and the adapter, and can enclose the impellercircumferentially. For specific applications, moreover, a hydraulic unitwith no heater can be attached to the adapter. The pump assemblynevertheless then provides the same drive module and the same adapter.The adapter and the drive module define common parts of the modular pumpassembly in this regard, whereas different hydraulic units are used andattached to the adapter for application-specific or customer-specificdesigns.

According to an embodiment of the invention, the intake port can beprovided on the first hydraulic unit and on the at least one additionalhydraulic unit coaxially to the shaft. The identical relativepositioning of the intake port on the different hydraulic unitsadvantageously results in a substantially identical or similar flowsituation for the pump assembly as a whole, regardless of whichhydraulic unit is attached to the adapter. In this regard, the pumpassembly can be fluidically optimized with the knowledge that theposition of the intake port always remains the same. Thus, favorableflow and good hydraulic efficiency are achieved for the pump assemblydespite the use of different hydraulic units.

According to an embodiment of the invention, the discharge port canproject radially or tangentially in the region of the tubular section.In this way, the hydraulic efficiency is advantageously further improvedwhen the liquid is deflected by only 90° on account of the relativearrangement of the discharge and intake ports.

According to an embodiment of the invention, a spiral baffle for theliquid can be formed in the region of the can flange. Provision canlikewise be made for the adapter to be designed with a spiral shape inthe region of the tubular section. In either case, the geometry improvesthe hydraulic efficiency of the pump assembly. Since the design measuresare provided in the region of the adapter, a favorable fluidic designand high hydraulic efficiency are the result regardless of the hydraulicunit used. In contrast to the practice that was customary heretofore,the design measures that affect the shape of the flow are not providedas part of the uniform hydraulic unit for installation, but instead areimplemented as part of the newly provided adapter.

According to an embodiment of the invention, the heater for the liquidcan be integrated in the end wall of the hydraulic unit. An advantageousresult of integrating the heater in the end wall is good efficiency inheat transfer. A large contact area and high turbulence of the flow inthe pump chamber benefit the heat transfer in this design. At the sametime, it has become apparent that the installation space situation inmany different applications allows for integration of the heater in theend wall.

According to an embodiment of the invention, a fastenor can be providedon the adapter. Also, a mating fastenor can be provided on the firsthydraulic unit and on the at least one additional hydraulic unit thatare designed such that they can be placed on the fastenor of the adapterto connect the components detachably or non-detachably. In this regard,either the first hydraulic unit or the second hydraulic unit can beplaced on the adapter. The fastenor of the adapter and the matingfastenor that is provided on the hydraulic units thus can be astandardized geometric interface. No adjustments to the design of theadapter are required for exchanging the hydraulic unit, and designadjustments in the region of the adapter can be avoided.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus, are not limitiveof the present invention, and wherein:

FIG. 1 is a cross-sectional representation of a pump assembly accordingto the invention comprising a drive module, and a first hydraulic unit,and an adapter that is provided between the drive module and the firsthydraulic unit,

FIG. 2 is a perspective view of the pump assembly from FIG. 1,

FIG. 3 illustrates the pump assembly according to an embodiment of theinvention with a second hydraulic unit secured to the adapter,

FIG. 4 is a perspective view of the pump assembly from FIG. 3,

FIG. 5 illustrates the pump assembly according to an embodiment of theinvention with a third hydraulic unit secured to the adapter, and

FIG. 6 is a perspective view of the pump assembly from FIG. 5.

DETAILED DESCRIPTION

A pump assembly according to the invention for water-carrying cleaningappliances as in FIGS. 1 and 2 comprises a drive module 1, a firsthydraulic unit 2, and an adapter 3, which is provided between the drivemodule 1 and the first hydraulic unit 2 and is connected to both ofthem. The pump assembly according to an exemplary embodiment of theinvention is designed as, for example, a circulation pump for a washingmachine or a dishwasher, and can be used in a commercial or homeenvironment.

The drive module 1 provides a stator 4, a rotor 6 held on a shaft 5 ofthe drive module 1 such that it can rotate relative to the stator 4, anda housing 7 that circumferentially encloses sections of the stator 4.Two plain bearings 8, 9 are provided to support the shaft 5. The drivemodule 1 functions in the manner of a synchronous motor, in particular.Accordingly, an air gap 10 between the stator 4 and the rotor 6 can berelatively large in design.

The drive module 1 is connected to the adapter 3. The adapter 3 has acan body 12 that encloses the rotor 6 circumferentially in the region ofthe air gap 10 and on an end face facing away from the impeller 11, acan flange 13 adjoining the can body 12 on a side facing the impeller11, and a tubular section 14 that extends essentially cylindrically. Thetubular section 14 encloses the impeller 11 circumferentially. Radiallyprojecting from the tubular section 14 is a discharge port 15, which isprovided for discharging the liquid circulated by the pump assembly 1.Plain water or water with added detergent is usually provided as theliquid.

The adapter 3 is designed as a single piece. The can body 12, the canflange 13, the tubular section 14, and the discharge port 15 areproduced in the present case as one common plastic component. The shaft5 is supported on the can body 12 by the plain bearing 9 on a sidefacing away from the impeller 11. The second plain bearing 8 issupported on the can flange 13 by a bearing carrier 16. The rotor 6 ofthe drive module 1 is implemented in this regard as a wet rotor.Accordingly, the liquid that is pumped by the pump assembly fills thecan body 12 of the adapter 3. As a result of the hermetic seal producedvia the can body 12 and the can flange 13, it is possible to dispensewith a dynamic seal or separation between components of the pumpassembly that move relative to one another.

The first hydraulic unit 2 connected to the adapter 3 provides an intakeport 17 arranged coaxially to the shaft 5 and an end wall 18 extendingradially thereto. The intake port 17 is two-piece in design. Itcomprises a first tubular part 19 and a second tubular part 20. Thetubular parts 19, 20 of the intake port 17 are placed one on the otherand connected together in an interlocking manner. An axially preloadedseal 21 is provided between the intake port 17 and the end face 18.Integrated into the end wall 18 is an electrically operated heater 32,which serves to heat the liquid pumped by the pump assembly. The heater32 is essentially saucer-like in design.

In order to connect the first hydraulic unit 2 to the adapter 3, afastenor 33 is provided on the adapter 3. The first hydraulic unit 2correspondingly provides a mating fastenor 34, which can be placed onthe fastenor 33. In the present case, the connection is implemented, forexample, through a snap closure. It is optionally possible to implement,for example, a bayonet mount or the like. A seal 22 is provided betweenthe hydraulic unit 2 and the adapter 3 in order to seal the pumpassembly.

In operation, the liquid is delivered in a pumping direction 23 throughthe intake port 17 to a pump chamber 24 accommodating the impeller 11.The pump chamber 24 is delimited circumferentially by the tubularsection 14 of the adapter 3 and at one end by the end wall 18 of thefirst hydraulic unit 2 and at the other end by the can body 12 and thecan flange 13 of the adapter 3. After pressurization, the liquid isdischarged through the discharge port 15, which is implemented as anintegral component of the adapter 3.

The pump assembly according to the invention is implemented in themanner of a modular pump assembly. FIGS. 3 and 4 show the pump assemblyaccording to the invention with the drive module 1 and the adapter 3. Inkeeping with the modular concept, a second hydraulic unit 25 is nowconnected to the adapter 3 instead of the first hydraulic unit 2. Thesecond hydraulic unit 25 dispenses with an integrated heater. Provisionis made for a flat end wall 26 that extends essentially radially, and anintake port 27 that is molded thereon. The intake port 27 is formed inthe region of an outer circumferential surface 28 for installation of atubular heater that is not shown, via which the liquid delivered throughthe intake port 27 is heated before entering the pump chamber 24 of thepump assembly. As usual, the adapter 3 and the second hydraulic unit 25are detachably connected to one another by the fastenor 33 and themating fastenor 34. The seal 22 is provided between the adapter 3 andthe second hydraulic unit 25 as before.

A third configuration of the pump assembly according to the invention,as shown in FIGS. 5 and 6, provides a third hydraulic unit 29 connectedto the adapter 3. The third hydraulic unit 29 is implemented without aheater. An intake port 30 and an end wall 31 radially projecting outwardtherefrom are made as a single piece with the mating fastenor 34.Otherwise, the adapter 3 employed and the drive module 1 are identicalto the previously shown configurations of the pump assembly according tothe invention.

The provision of a single drive module 1 and an adapter 3 that is alwaysidentical and the plurality of the hydraulic units 2, 25, 29 makes itpossible to customize the pump assembly according to the invention in avery specific and needs-based way for different applications orcustomer-specific desires and specifications. The always identicallyconstructed drive module 1 and the always identically constructedadapter 3 can be mass-produced. An application-specific adaptation isthen carried out in the region of the hydraulic unit 2, 25, 29. Themodifications in the region of the hydraulic unit 2, 25, 29 make itpossible to adapt the pump assembly to specific spatial conditions.Because important fluidic components of the hydraulic unit 2, 25, 29,such as the position and arrangement of the discharge port 15, areimplemented separately in the region of the adapter 3, extensivehydraulic dimensioning, analysis, and testing of theapplication-specific hydraulic units 2, 25, 29 are largely eliminated.The fluidic properties of the pump assembly are accordingly definedsubstantially by the geometry of the adapter 3 and are largelyindependent of the structural design of the hydraulic units 2, 25, 29.

In order to optimize hydraulic efficiency, a spiral baffle for theliquid can be implemented on the adapter 3 in the region of the canflange 13. Also, the adapter 3 can be designed with a spiral shape inthe region of the tubular section 14, with a flow cross-sectionincreasing toward the discharge port 15.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are to beincluded within the scope of the following claims.

What is claimed is:
 1. A pump assembly for water-carrying cleaningappliances, the pump assembly comprising: a drive module with a stator,a rotor held on a shaft of the drive module so as to be rotatablerelative to the stator, and a housing that circumferentially encloses atleast sections of the stator; an impeller for pumping liquid that isheld on the shaft; a hydraulic unit with an intake port through whichthe liquid is adapted to be delivered to the impeller; and an adaptedarranged between the drive module and the hydraulic unit, the adapterbeing connected on one side to the drive module and on the other side tothe hydraulic unit, the adapter comprising: a can body that extendsbetween the rotor and the stator of the drive module, and encloses therotor on an end face facing away from the impeller; a can flangeadjoining the can body on a side facing the impeller, the can flangeprojecting radially outward from the can body at least in sections; atubular section that circumferentially encloses the impeller at least inpart and that delimits a pump chamber containing the impeller; and adischarge port formed on the tubular section for discharging the liquidfrom the pump chamber.
 2. The pump assembly according to claim 1,wherein the pump assembly is a modular pump assembly and has a firsthydraulic unit and at least one additional hydraulic unit, wherein achoice of the first hydraulic unit or the at least one additionalhydraulic unit is attached to the adapter on a side opposite the drivemodule, and wherein at least the first hydraulic unit or the at leastone additional hydraulic unit has a heater for heating the liquid. 3.The pump assembly according to claim 1, wherein the intake port on thefirst hydraulic unit and the intake port on the at least one additionalhydraulic unit are provided coaxially to the shaft.
 4. The pump assemblyaccording to claim 1, wherein the hydraulic unit provides an end wallthat radially encloses the intake port, and wherein, together with thetubular section of the adapter, the can body and the can flange delimitsthe pump chamber.
 5. The pump assembly according to claim 1, wherein aspiral baffle for the liquid is arranged in the region of the canflange.
 6. The pump assembly according to claim 1, wherein the intakeport is multipart in design, wherein a first tubular part of the intakeport and a second tubular part of the intake port are placed one insidethe other and snapped together, and wherein a preloaded axial seal isprovided between the two tubular parts and/or between one tubular partand the end wall of the hydraulic unit.
 7. The pump assembly accordingto claim 1, wherein the heater for the liquid is integrated in the endwall of the hydraulic unit.
 8. The pump assembly according to claim 1,wherein the heater is a tubular heater, and wherein the tubular heateris provided between an end wall of a hydraulic unit and the tubularsection of the adapter or in a region of the intake port upstream of thehydraulic unit or in the pump chamber adjacent to an innercircumferential surface of the tubular section between the can flange ofthe adapter and the end wall of the hydraulic unit.
 9. The pump assemblyaccording to claim 1, wherein the discharge port projects radiallyand/or tangentially from the tubular section.
 10. The pump assemblyaccording to claim 1, wherein the adapter has a spiral shape in a regionof the tubular section.
 11. The pump assembly according to claim 1,wherein, in order to detachably connect the adapter to any desiredhydraulic unit, a fastenor is provided on the adapter, and wherein amating fastenor is provided on the first hydraulic unit and on the atleast one additional hydraulic unit such that the mating fastenor of thefirst hydraulic unit and the mating fastenor of the at least oneadditional hydraulic unit are placed on the fastenor of the adapter.